description of two species of palmoxylon-one new

1888.]

PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 89

DESCRIPTION OF TWO SPECIES OF PALMOXYLON-ONE NEW—

FROM LOUISIANA.

BY F. H. KNOWLTON, ASS'T CURATOR FOSSIL PLANTS.

(With Plate xxx.)

On

February29,1880,several specimen's offossil palms werereceived in the

Department

of Fossil Plants of the U. S. National

Museum

that

had

beencollected

by

Mr.LewisC.Johnson,of theU.S.GeologicalSur- vey, inEapides Parish, Ln.

They

appeared to be very wellpreserved fragments, in

some

cases nearly 8 inches indiameter,

and

from 3toa inchesin length.

They

arecompletelysilicified,

aud

are yellowish-gray incolor.

The

fibro-vascular bundles

show

verydistinctly intransverse section,andtheirirregularorundulatingcoursethroughthe stoneisalso clearly

shown when

broken longitudinally.

The

difficultiesinthe

way

of the satisfactory determination of

mono

cotyledons,

by

a study of iuterual structure alone, are

much

greater than the determination from similar parts of conifers ordicotyledons.

The

reasonsfor this are, that monocotyledonous stems are in general lesssusceptible of satisfactory preservationin thefossil state, consist- ingasthey do largelyof

parenchematous

tissue, with largeintercellu- larspaces;

and

alsobecause the studyof livingforms, which furnishes the basis for all studies of fossil forms, has not been as exhaustively undertaken. Particularly is this true of the study offossilpalms.

So

little isat present

known

regarding the internalstructure of theliving- species thatit isonly _possiblein the presentstateof our

knowledge

to mass together all the fossil species under the comprehensive generic

name

of Palmoxylon, or simply " palm-wood." Itis true that the de- scribed species of Palmoxylon differ considerably

among

themselves, and it is

more

thanprobablethat characterswillultimatelybe obtained that willallow of a separation into several generic types.

Two

generic types, Fasciculites

and

Palmacites, were recognized by the earlier writers, mainly from the microscopic appearance of the trunks; but Schenk,

who had

opportunity of studying

much

of the originalmaterial as preserved in the Dresden

Museum,

concluded that

it wason thewholebesttorecognize only asinglegenerictype, forwhich he proposed the

name

Palmoxylon.*

The

most complete enumeration of speciesis thatgiven by Dr. Felix in his exhaustive paperon theFossil

Woods

ofthe

West

Indies.t

Most

of the speciesmentioned

come

from the islandofAntigua, butseveral arefrom

European

localities.

"Eagler's Botan. Jakrb.,Vol. in, 1882, p. 355.

tDie loss. Holz.Westhulieus. Samuil. palaout, Abhaudl.,Ser.i, Heft 1. Cassel, 1883,pp.22-27, PI. iv, v.

90 DESCRIPTION OF

SPECIES

OF PALMOXYLON.

The

^speciesare divided

by

Felix into

two

sections, thefirstofwhichin-

cludes those having selereuchyma bundles ^scattered between thefibro.

vascular bundles, and the second ofwhichincludes the species without sclerenchyma ^bundles.

The

first sectionincludes most of the ^species described

by

Felix.

The two

species from Louisiana represent both sections.

The

species belonging- to the first section I

am

inclined to identify with aspecies described

by

^Felix,from Antigua, although ^it differs

from itin

some

^{relativelyimportant features.}

PalmoxylonQuenstedtiFelix,Foss. Holz. Westindiens,p25, PI. iv,fig. 4.

Described

by

Felix as follows: Fibro-vascular bundles extraordi- narily numerous, the bast portion strongly developed,

and

the xylem portion very

much

reduced, or notwellpreserved.

Sometimes

the 1>ast

portionsurrounds the

xylem and

sieve tissues,soasto give the appear- anceoftheir lyinginan opening^{ofthe basttissue.}

Numerous

isolated bundles(Faserbiindeln) of very considerable^sizeappear aboutthefibro- vascular bundles.

The

fundamental or parenchymatous tissue is com- posed of long, butrather ^small,cellswithoutintercellular spaces.

The

form fromLouisiana agrees^wellwiththis description, buthasuot beenas well preserved.

The

fibro-vascuhir bundles

have

beenverynu- merous,particularly near ^theperiphery of the stem, asalso

have

been the smallersclerenchyma^bundles.

The

fundamental^tissuehasnot been preserved except in immediate contactwiththefibro-vascular bundles. Itisthenseentobe comp<^»seq ofsmall,nearlyregular,cells,with fewsmallintercellularspaces

among

them.

The

specimens

from Antigua upon

^whichthis species isfounded,were

first collected

by

Quenstedt in 18G7,*

who

recognized at once ^their

palm

like structure.

They

wereopalized ina verybeautiful manner.

Palmoxylon cellulosum, n. sp. Platexxx,tig.2.

Thisspecies, as stated above, belongs^tothe section characterized by theabsence of sclerenchyma bundles^{outside of}

and among

^thefibro-

vascular bundles.

The

fundamental ^{tissue is}

composed

of large, irregular ^cells, between which are very large intercellular spares

The

^{tissue is}

more compact

inthevicinity of the bundles, but^{is loose}

and spungy

in general.

The

fibro-vascular bundles have been

modes

ately numerous.

They

are large, usually^ellipticalinoutline.

The

^bast

cells are large, with the

lumen

reduced to a

minimum,

while the xylem portionisnearly completely surrounded.

The

fundamental ^tissueof this species bearsa strong resemblanceto that^of PalmoxylonlacunosumFelix,

and would

bereferred to itbutfor the absence ^of the isolated sclerenchyma bundles, which ^so clearl

"

marks

thespeciesof^Felix.

KapidesParish, the ^localityfrom which these fossils were obtained,

"liaudbuck^tl. Fetrelactenkunde,^2.Autl., p. 883.

;i)

St

to

ProceedingsU.S.NationalMuseum,Vol. XI, 1888,-Knowltor

Plate XXX.

Fig. 1. Palmoxylon _QuensiedtiFelix. (Page90.i Fig.^>. Palmoxyloncellulosum,n. sp. (Page90.i

1888.]

PKOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 91

is thought

by

the collector,Mr.Johnson,to be ofPliocene Age. Itbe- longs, as I

am

informed

by

Mr.

W.

J.

McGee,

of the IT. S. Geological Survey, to the

Grand

GulfofHilgard, a formation usually regarded as Miocene,but concerning the age of which

we

really

know

very little,

and all determinations of position

must

be regarded as tentative until more complete data are obtained.

The

geologic horizon from which the Palmoxylon Quemteclti Felix wasobtainedis alsoindoubt. Hovey,

who

has contributed a paperon the Geology of Autigua,* inclines to regardit as belonging to the younger Pliocene,butFelixtthinksit

may

possiblybe older. It would beinterestingifthis localitycould be correlated with thatfrom Louisi- ana, butin the present state of our

knowledge

this is manifestly im- possible.

*Aui.Jomn.Sci.,Vol.xxx, 1639, pp. 75-85. L.c,p.^8.

Proc.N.

M.

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